Vertically Adjustable Breakout Wrench

ABSTRACT

A hydraulic breakout wrench with an adjustable height mounting for loosening threaded connections of large diameter drilling members. The wrench includes a swing body pivotally attached to the adjustable height mounting, a clamping jaw mounting one of two clamping elements, a hydraulically actuated clamping lever. A clamp holder, which is pivotally connected to the clamping lever and also connected by a pivoted link to the clamping jaw, mounts the second clamping element. The clamping jaw is slidably mounted on the swing body and is normally urged to a retracted position by a passive hydraulic cylinder. The clamping lever is pivoted on the clamping jaw and is biased into an open position. A hydraulic cylinder, connecting the swing body and the lever, provides both gripping force and rotational torque to the drilling member. The adjustable mounting is hydraulically actuated and has two telescopic stages for an optimum range of height adjustment.

FIELD OF THE INVENTION

The application field is the loosening of threaded joints, and in particular joints of large diameter round components such as those found in the drill rigs of the mining industry.

In mining field, large diameter drills are made up of tubes that are screwed together to transmit the thrust force and the torque applied to the tool that makes the hole. The drills are equipped with hydraulic devices to loosen the joints between the pipes. Commonly these devices are called breakout wrenches.

BACKGROUND OF THE INVENTION

Earlier wrenches have several known shortcomings:

One of those is that earlier wrenches tend to have an insufficient grip on the drill pipe or bar (hereinafter generically referred to as drilling member) when the required loosening torque is high.

U.S. Pat. No. 6,012,360 (shown in FIGS. 1-3 hereof), solved the technical problem of insufficient grip when the torque for loosening is high, using a mechanism by which the gripping force automatically increases with the applied torque. However, the aforesaid invention does not solve the technical problem generated by wear or loss of diameter of the drilling member to be released, nor does it easily accommodate gripping of the drilling member by the wrench at an optimum height in the drill rig.

Usually the drilling member to be loosened decreases in diameter by wear during the course of a drilling operation. This causes the drilling element to be received deeper within the jaws of the wrench and causes the jaws to be disposed at a smaller angle in order to grip the drilling element. As a result, the clamp element 7 (insert) carried by the lever 4 then only partially rests on the drilling member, thus decreasing the contact surface. But since the required torque remains the same or may be even higher than usual, the stress on the clamp element 7 in contact with the drilling member can become much higher than the normal design stress, causing the clamp element to rupture or damage the lever 4 with the consequent loss of production time, since it is necessary remove the wrench from its position on the drilling member and change the clamp element 7, or possibly the complete lever 4, as the case may be.

In addition to the above, the optimum gripping section of the drilling members can vary in location, and can be in areas of greater or lesser height respect to wrench. The present invention solves this problem and additionally permits the adjustment of the wrench axially with respect to the drilling members, because the pedestal on which the wrench is mounted has been designed to permit changing the vertical position of the wrench. To this end, the invention includes a pedestal which is hydraulically adjustable in height, which enables the wrench to be adjusted vertically to a section of the drilling member desired to be engaged by the wrench.

In FIGS. 1, 2 and 3 of the drawings there is an example of the prior art breakout wrench of U.S. Pat. No. 6,012,360. The patented wrench includes a swing body 3 comprised of spaced-apart swing body elements joined at a common pivot element 30 and mounting a clamping jaw 5 by means of a pin 10 extending laterally from the jaw 5 and sliding in arcuate guide slots 15 provided in the swing body elements. The pin 10 also connects with a passive cylinder 2, which tends to retract the pin 10 while allowing it to be moved in the arcuate slots 15. The jaw 5 carries a clamping element 6 for engagement with a drilling member 31.

The jaw 5 is made up of two spaced apart elements joined together and mounting a pivot pin 14 by which a clamping lever 4 is mounted. The lever 4 carries a clamping element 7 at one end and is connected to hydraulic cylinder 1 at its other end. The cylinder 1 is also connected to the swing body 3 so as to be able to apply force to the lever 4, first to grip the drilling member 31 and thereafter to rotate the gripped section. As described in U.S. Pat. No. 6,012,360, the forces applied to the lever 4 are such that the gripping force applied by the lever and its clamping element 7 are always proportional to the resistance of the drilling member 31 to rotation. The entire disclosure of U.S. Pat. No. 6,012,360 is hereby incorporated herein by reference.

Design differences between U.S. Pat. No. 6,012,360 patent and the present invention include the following:

In the mechanism of the present invention (FIGS. 4-9), the clamp element 47 is mounted by a clamp holder 49, instead of being attached directly to the lever 44. One end of the clamp holder 49 is joined to the end of the lever 44 by a pin 51. The other end of the clamp holder 49 is connected to the jaw 45 by means of a connecting link 48 containing openings 56 and 57 which connect it to the clamp holder 49, by means of a pin 42, and to the jaw 45 by means of a pin 53.

The present invention also includes a pedestal 59 (FIGS. 4, 8 and 9) which mounts the wrench and enables height adjustment of the wrench assembly relative to a drill member held vertically in a drill rig. The pedestal has a base fixed to the drill structure adjacent to the drill member. Internal hydraulic mechanisms, to be described, enable an upper sector of the pedestal, on which the wrench is mounted, to be raised and lowered to position the wrench at an optimum height at which to grip the drill member.

The device of patent number U.S. Pat. No. 6,817,271 is different in the way it grips the bar and includes only one hydraulic cylinder with one jaw and does not include a height adjustable pedestal.

U.S. Pat. No. 8,453,542 shows a breakout wrench, in which the loosening torque is not proportional to the applying force, such that it slides when applying torque. U.S. Pat. No. 9,181,766 is similar to U.S. Pat. No. 8,453,542, in that the loosening torque is not proportional to the applying force.

US publications 20090205442 and 20090211405, show other designs of breakout wrenches. None of the foregoing include a height adjustable pedestal.

SUMMARY OF THE INVENTION

The breakout wrench assembly of the invention incorporates in an advantageous and synergistic manner a vertically adjustable pedestal structure in combination with a breakout wrench which is enabled to grip a drilling member with force that automatically increases with the torque required to rotate the drilling member and which further compensates effectively for decrease in the external diameter of the drilling member as a result of wear. The assembly significantly improves the efficiency with which breakout operations may be performed.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1-3 are illustrations of embodiments of a prior art wrench according to U.S. Pat. No. 6,012,360.

FIG. 4 is an isometric view of the assembly of the invention illustrating the improved breakout wrench and the vertically adjustable pedestal on which it is mounted.

FIG. 5 is an elevational view, with parts broken away, of an improved breakout wrench forming part of the present invention.

FIG. 6 is an isometric view of the wrench shown FIG. 5.

FIG. 7 is an exploded view of the wrench shown in FIG. 5

FIG. 8 is a front elevational view of the adjustable height pedestal, shown in FIG. 4, for mounting of the wrench of FIG. 5.

FIG. 9 is a side elevational view, partly in section, of the pedestal shown in FIG. 8.

DETAILED DESCRIPTION OF THE INVENTION

The present invention, shown in FIGS. 4-9, comprises a height adjustable hydraulic wrench for loosening large diameter threaded drilling members, which includes a swing body 43 pivotally attached to a pedestal 59, capable of adjusting the height of the wrench. The wrench includes a jaw 45 mounting a clamping element 46 and a clamping lever 44. The swing body 43 comprises spaced apart plates provided with a pair of arcuate guide slots 55. The jaw 45 is mounted on the swing body 43, by means of a guide pin 50 which is received in the guide slots 55. A passive hydraulic cylinder 42 and a spring 60 urge the jaw 45 into a retracted rest position with respect to the swing body 43, in which the guide pin 50 is fully retracted within the guide slot 55, as shown in FIGS. 4 and 6. The passive cylinder 42 is connected to the swing body 43 by a pin 63 and to the jaw 45 by means of the guide pin 50.

The clamping lever 44 is pivotally mounted on the jaw 45 by means of a pin 54, and is also connected by a pin 61 to an active hydraulic cylinder 41. The cylinder 41 is also connected to the swing body 43 by a pin 62. When retracted, the active cylinder 41 directs the clamping lever 44 towards an open position relative to the jaw 45. The active cylinder 41 provides both gripping force and torque to the drilling member to be loosened in a proportional way. In this respect, when the cylinder 41 is extended the clamping lever is first moved in a closing or clamping direction until the drilling member 31 is engaged. During this initial movement of the clamping lever, movement of the jaw 45 is restrained by the passive cylinder 42 and spring 60. Thereafter the clamping pressure applied by the cylinder 41 and clamping lever 44 continues to be increased, gripping the drilling member 31 more tightly, until the drilling member is forced to rotate.

The illustrated wrench incorporates a clamp holder 49, which mounts the clamping element 47 and guides and orients the clamping element 47 to make a correct grip of the drilling member 31 notwithstanding that the drilling member may have been worn to a smaller diameter through usage. The inner end of the clamp holder is pivotally connected to the clamping lever 44 by a pin 51 such that the clamp holder 49 is moved toward the drilling member as the lever 44 is rotated in a clamping direction by the active cylinder 41. The outer end of the clamp holder 49 receives a pin 52 which joins it with the connecting link 48 through an opening 56 in one end of the connecting link. Another opening 57, in the opposite end of the connecting link 48, receives a pin 53 that joins the connecting link 48 to the jaw 45. The clamp holder 49 maintains a desired orientation of the clamping element 47 as the clamping lever 44 advances the clamp holder toward the drilling member 31. Initially, the connecting link 48 is disposed at an acute (i.e., less than 90 degrees) angle with respect to the clamp holder, as is evident in FIG. 5. When the clamping lever 44 is advanced farther than is normal, because of a reduced diameter of the drilling member 31, the connecting link 48 is caused to assume a larger angle with respect to the clamp holder to reposition and reorient the clamping element 47 for a more optimal grip on the smaller drilling member.

A height adjustable pedestal 59 raises or lowers the complete wrench assembly to the correct position for engaging and gripping the drill member. The illustrated adjustable pedestal comprises upper and lower vertically movable pedestal sections 70, 71. The lower section 71 includes an external housing 72 which is telescopically engaged with and supported by an internal guide structure 73. The internal guide structure 73 has a base 74 which is fixed to a base of the drill rig (schematically illustrated at 81 in FIG. 4) in a position adjacent to the vertical axis of the drill member (schematically indicated at 82 in FIG. 4). A hydraulic cylinder 75 is connected to the base 74 and to the eternal housing 72 by which the latter can be moved vertically up or down, guided by the internal guide structure 73.

The upper pedestal section 70 has a telescopic structure including a base 76 which is fixed to the top of the external housing 72 portion of the lower pedestal section 71. The upper pedestal section 70 has an internal guide structure 77 which supports and guides a movable outer section 78 for vertical adjusting movements. A hydraulic cylinder 79 connects the base 76 and the movable upper section 78 for controllably extending the upper section 78 vertically. The movable upper section 78 mounts a vertically spaced pair of lug elements 79 arranged for receiving a pin 80 for pivotal mounting of the swing body 43. As reflected in FIG. 4, the mounting of the wrench on the pedestal 59 allows the wrench to be pivoted out away from the drill axis during normal drilling operations, while allowing the wrench to be pivoted to a positioned aligned with the drill axis 82 to grip a drill member for breakout operations. A hydraulic cylinder 83 is connected between the wrench and the pedestal for controlled pivoting of the wrench between its retracted and operating positions.

In a preferred embodiment, illustrated in FIGS. 8 and 9, the upper telescopic pedestal section 70 is offset substantially toward one side of the lower section 71. In the illustrative but non-limiting structure of FIGS. 8 and 9, the vertical axis of the upper actuator 79 is positioned near the side edge of the lower telescopic housing 72, spaced substantially from the axis of the lower actuator 75.

The two independently adjustable pedestal sections 70, 71 enable the wrench to be positioned in a wide range of vertical positions, for optimum engagement of the wrench with the drilling member section to be separated.

It will be understood that the invention hereof is not limited to the specific form thereof herein illustrated and described in detail and that changes and variations may be made therein without departing from the clear teachings of the invention disclosure. Accordingly, reference should be made to the following appended claims in determining the full scope of the invention. 

What is claimed is:
 1. A height-adjustable hydraulic wrench for loosening threaded connections of pipes and other drilling members used in drilling machines, which comprises: a height-adjustable mounting mechanism; a main wrench body pivotally attached to a vertically movable portion of the mounting mechanism; a clamping jaw connected to the main wrench body, said clamping jaw having a first clamping element for gripping one side of the drilling member; a clamping lever pivotally attached to the said clamping jaw; a clamping element holder movably connected to the said clamping lever and to said clamping jaw, said clamping element holder mounting a second clamping element for gripping an opposite side of the drilling member; and a first hydraulic cylinder connected at a first end thereof to the main wrench body and at a second end thereof to the clamping lever.
 2. A hydraulic wrench according to claim 1, wherein said height-adjustable mounting mechanism includes one or more hydraulic actuators for adjusting the height of the wrench.
 3. A hydraulic wrench according to claim 1, wherein said main wrench body is pivotally attached to the height-adjustable mounting mechanism and has an arcuate guide associated with said clamping jaw that allows the clamping jaw to move in an arcuate manner relative to said main wrench body for making a loosening movement on a drilling member gripped thereby.
 4. A hydraulic wrench according to claim 3, wherein said clamping jaw is pivotally attached to one end of a passive hydraulic cylinder biased to urge said clamping jaw to a retracted position in said main wrench body, whereby an initial gripping movement of the wrench takes place by a pivoting movement of said clamping lever relative to said clamping jaw, and upon engagement of said drilling member by said second clamping element, a rotational loosening movement is started, in which the clamping jaw is caused to move through said arcuate guide in the main wrench body, generating the rotational loosening movement of the clamping jaw.
 5. A hydraulic wrench according to claim 1, wherein said clamping lever, upon the initial application of force by the first hydraulic cylinder, generates a gripping force on the drilling element, and upon continued application of force generates a loosening torque by rotational movement of said clamping jaw.
 6. A hydraulic wrench according to claim 1, wherein said clamp holder is connected at one end to said clamping lever and at an opposite end to said clamping jaw on which said first clamping element is mounted, and the clamp holder guides said second clamping element to a correct position to grip a drilling element.
 7. A hydraulic wrench according to claim 6, wherein the opposite end of said clamp holder is connected to said clamping jaw by a pivotally mounted connecting link.
 8. A hydraulic wrench according to claim 1, wherein said height-adjustable mounting mechanism comprises upper and lower height adjustable sections, with said upper section being mounted on a vertically adjustable portion of said lower section.
 9. A hydraulic wrench according to claim 8, wherein a separate hydraulic actuator is provided for each of said height adjustable sections.
 10. A hydraulic wrench according to claim 9, wherein a vertical center line of said upper height adjustable section is offset with respect to a vertical center line of said lower height adjustable section.
 11. A hydraulic wrench according to claim 9, wherein each of said height adjustable sections is constructed of inner and outer telescopically movable portions, with the inner telescopic portion of the upper section mounted on the outer telescopic portion of the lower section. 